Noisy pixelated lightbulb filament emitter
I love mesh lights so I use Branched Path Tracing &amp; the Light Paths settings to get rid of fireflies and noise. 

I get good results in most situations by, in the Sampling Panel, choosing Branched Path Tracing and setting Clamp Indirect to something between 0.1 and 0.5 and setting the Mesh Light Samples to 3ish.

In the Light Paths Tab, I set Max Bounces, Diffues, Glossy, and Transmission to 2. Lastly, you can check Denoising in the Layers tab to clean up any remaining noise. I just leave the defaults.

Attached pic has at least 7 mesh lights and used only 250 samples.(So you can still see some denoising artifacts, but for super low samples, not bad.)